Establishment of an experimental model of high metastasis of human gastric cancer in nude mice with intact tissue blocks planted in situ

Summary

The establishment of an in situ planting metastasis model in nude mice with intact tissue blocks of human gastric cancer can: (1) study the mechanisms of tumor infiltration and metastasis; (2) explore the methods of blocking tumor

(2) explore the methods to block the tumor metastasis; (3) establish a model that can reflect the clinical metastasis of human gastric cancer.

Operation method

In situ implantation of intact tissue blocks

Principle

Human gastric adenocarcinoma SGC27901 cell line was injected subcutaneously into nude mice (2x106/L cell suspension), and solid tumors were formed by repeated passaging after tumor formation. The 6th generation of tumor source was used as the tissue material, and the abdominal cavity was opened, and the tumor was pasted onto the nude mice at the gastric wall of the gastric curvature where blood vessels were thickly distributed by the bioadhesive method using OB medical bioadhesive; and when the tumor-bearing mice were on the verge of dying, the tumor-bearing mice were executed and dissected for examination.

Materials and Instruments

BALB c nu nu nude mouse Human gastric adenocarcinoma cell line SGC-27901
Ketamine Formaldehyde Paraffin
Needle OB Bio-glue Toothless tweezers Silk thread Optical microscope

Move

I. Establishment and Transmission of Subcutaneous Implantation Tumor Models

Twenty-four BALB/c nu/nu nude mice, males, 6 weeks old, body mass 18-20 g, were raised under SPF grade conditions. Human gastric adenocarcinoma cell line SGC-27901 was injected subcutaneously into nude mice with ^2x106/L cell suspension, and solid tumors were formed by repeated passaging after tumor formation, and the tumor source of this group was the 6th generation.
II. Establishment of in situ planting model of human gastric cancer tissue block in nude mice
1. The experimental animals were fasted for 12 h before the operation, anesthetized with ketamine 50 mg/kg, routinely sterilized, and selected to enter the abdomen through a left median incision, exposing the stomach wall, and then the plasma muscular layer of the stomach wall was scratched with a 1 mL sterile empty needle at the greater curvature of the stomach near the gastric sinus, and the damaged area was pushed inward with toothless forceps, so as to make the local gastric wall form a niche, and then a tumor was implanted, and one drop of OB biogel (provided by Guangzhou Baiyun Medical Gel Co.) was placed on the surface of the tumor to form an in situ planting model. After about 40 s of solidification, the gastric wall was returned into the abdominal cavity, and the peritoneum and skin were closed with No. 0 silk suture. 2.

2. The whole process strictly followed the aseptic operation. 3.

3. All model animals were kept without any anesthesia accident and in SPF grade. 4.

4. 2 animals died within 1 week after the operation. 5.

5. Observe all nude mice regularly for general condition, movement and abdominal signs. 6.

6. When the tumor-bearing mice showed obvious signs of exhaustion such as emaciation, bowed back, and depression, the mice were dissected by cervical dissection, and in situ tumors, enlarged lymph nodes, thoracic and abdominal organs, and ascites were collected.

7. The specimen should be fixed with 10% formaldehyde, embedded in paraffin, sectioned, stained with H-E and examined by histopathology.

8. Chromosome identification of solid tumor cells.

Common Problems

I. Experimental discussion

Although in vitro experiments can reflect the motility and invasive ability of gastric cancer cells to a certain extent, they cannot completely replace the organ environment and metastatic effect of gastric cancer metastasis in vivo, so in vivo transplantation model has become the main method for experimental study of tumors. In the past, subcutaneous transplantation was the most common method, but metastasis may be less due to the encapsulation of the subcutaneous fibrous envelope. Recent studies have shown that in situ transplantation of tumor cell lines in nude mice cannot fully express the biological characteristics of the tumor, while in situ transplantation of intact tissue blocks can significantly increase the metastasis rate.

The human gastric cancer SGC27901 cell line is a poorly differentiated adenocarcinoma, which is suitable as a metastasis model material. In this experiment, SGC27901 cell line was used to establish a metastasis model in nude mice with subcutaneous transplantation of tumor blocks, which completely reproduced the metastatic process of gastric cancer, and provided an ideal animal model for the study of the growth and metastatic mechanism of human gastric cancer as well as anti-metastatic treatment.

There are 46 human chromosomes, and the position of each chromosome's attachment point is constant. According to the position of its attachment point, it can be classified into 4 categories, i.e., central, sub-central, sub-proximal, and proximal attachment points, and all the tissues of mice have end-telomeric attachment points, so the tumors formed in human tissues can be detected by chromosome identification technology. This is a simple, sensitive and reliable method for the detection of metastatic foci in various animal models.

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